wire to nowhere

[losingmytools]

I have just started re-wiring the lights upstairs, as I am putting flooring down in the loft. But when I came to the stair lighting I am at a loss as to how this light worked in the first place. It is a two-way switch, there are 4 cables from the light fitting, one is the power supply from downstairs, two run power to other rooms upstairs and ONE goes to one of the swtiches. This last cable is made up of a live wire and an earth wire. There is then another cable from the 1st switch to the 2nd switch, but as far as I can see there is another cable which then runs from the 2nd switch to NOWHERE. It should go back the light fitting, to complete the loop, but does not. HOW has my stair lighting worked all these years?

 

[ban-all-sheds]

as far as I can see there is another cable which then runs from the 2nd switch to NOWHERE.

So if you disconnect this cable at the 2nd switch, everything still works as before, does it?

 

[comms]

Take a look in the for refrence section at the top of the page.
The 2 switches are connected by 3 core & earth (usually) only one of the lights will have cable upto the light fitting (from L1 & L2), this is the most common method of converting oneway switching into twoway switching.

 

[ban-all-sheds]

Or live feed into bottom switch COM, T/E linking L1 & L2 to top switch, switched live out of top switch COM.

 

[losingmytools]

I will try disconecting the eroneous cable and see what happens.

Thanks